Fix #166 : DNS Support

docs/data-model/dns.md

@@ -0,0 +1,41 @@
+The DNS component of NetBox deals with the management of DNS zones.
+
+# Zones
+
+A zone corresponds to a zone file in a DNS server, it stores the SOA (Start Of Authority) record and other records that are stored as Record objects.
+
+Zone objects handle only forward DNS, reverse DNS is handled by Prefixes (in IPAM section), which also store a SOA record.
+
+Netbox provides two views in the DNS menu to get the exports in BIND format, which is compatible with every DNS server, directly or by import. Those
+exports are also accessible as JSON through the REST API. One of these views is the export of all the forward zones in the database,
+the second is the export of all the reverse zones.
+
+The reverse zones are correctly merged and/or divided to meet the requirements of a DNS server (for instance, IPv4 reverse zones must be /16 or /24), and
+not to duplicate records (for instance if you have in database the prefixes 192.168.0.0/16 and 192.168.1.0/24, only the biggest will be exported) ; however,
+only IP addresses which are in an active prefix will be taken into account. Obviously, reverse DNS is supported for both IPv4 and IPv6.
+
+The SOA Serial field is not editable : it's automatically created and managed by Netbox. Each time a zone (forward or reverse) is exported,
+if there are changes since the last export or if it's the first export, the serial will be incremented. It's in the following format :
+YYYYMMDDNN with Y the year, M the month, D the day and N a two-digit counter.
+
+As zones and their BIND exports are readable through the REST API, it is possible to write some external script to automatically update
+your DNS server configuration from Netbox's database.
+
+---
+
+# Record
+
+Each Record object represents a DNS record, i.e. a link between a hostname and a resource, which can be either an IP address or a text value,
+for instance another name if the record is of CNAME type.
+
+Records must be linked to an existing zone, and hold either an IP address link or a text value. The "Address" field points to an IP address
+in database, but if you want to put an IP in your record but not in your database (if you don't own the IP for instance), it's possible
+by putting the IP as text value instead.
+
+You can create, edit or import records with IPs not existing yet in the database. They will be automatically created (but not the prefixes !).
+However, the zones must be created first, they won't be so automatically.
+
+Reverse DNS is not supported by Record objects, but by the "PTR" field in IP addresses. If this field is modified and not empty, a corresponding
+A/AAAA record is automatically created if the corresponding zone is found in the database. Be careful, if there was A/AAAA records
+for the old PTR value, they are not deleted.
+

docs/index.md

@@ -3,6 +3,7 @@
 NetBox is an open source web application designed to help manage and document computer networks. Initially conceived by the network engineering team at [DigitalOcean](https://www.digitalocean.com/), NetBox was developed specifically to address the needs of network and infrastructure engineers. It encompasses the following aspects of network management:
 
 * **IP address management (IPAM)** - IP networks and addresses, VRFs, and VLANs
+* **DNS management** - DNS zones and records
 * **Equipment racks** - Organized by group and site
 * **Devices** - Types of devices and where they are installed
 * **Connections** - Network, console, and power connections among devices

netbox/dns/__init__.py

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+default_app_config = 'dns.apps.DNSConfig'

netbox/dns/admin.py

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+from django.contrib import admin
+
+from .models import (
+    Zone, Record,
+)
+
+
+@admin.register(Zone)
+class ZoneAdmin(admin.ModelAdmin):
+    list_display = ['name', 'ttl', 'soa_name', 'soa_contact', 'soa_serial']
+    prepopulated_fields = {
+        'soa_name': ['name'],
+    }
+
+
+@admin.register(Record)
+class RecordAdmin(admin.ModelAdmin):
+    list_display = ['name', 'zone', 'record_type', 'priority', 'address', 'value']

netbox/dns/api/serializers.py

@@ -0,0 +1,42 @@
+from rest_framework import serializers
+
+from ipam.api.serializers import IPAddressNestedSerializer
+from dns.models import Zone, Record
+
+#
+# Zones
+#
+
+
+class ZoneSerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = Zone
+        fields = ['id', 'name', 'ttl', 'soa_name', 'soa_contact', 'soa_serial', 'soa_refresh', 'soa_retry', 'soa_expire', 'soa_minimum', 'extra_conf', 'description']
+
+
+class ZoneNestedSerializer(ZoneSerializer):
+
+    class Meta(ZoneSerializer.Meta):
+        fields = ['id', 'name']
+
+
+#
+# Records
+#
+
+
+class RecordSerializer(serializers.ModelSerializer):
+
+    zone = ZoneNestedSerializer()
+    address = IPAddressNestedSerializer()
+
+    class Meta:
+        model = Record
+        fields = ['id', 'name', 'record_type', 'priority', 'zone', 'address', 'value', 'description']
+
+
+class RecordNestedSerializer(RecordSerializer):
+
+    class Meta(RecordSerializer.Meta):
+        fields = ['id', 'name', 'record_type', 'zone']

netbox/dns/api/urls.py

@@ -0,0 +1,19 @@
+from django.conf.urls import url
+
+from .views import *
+
+urlpatterns = [
+
+    # Zones
+    url(r'^zones/$', ZoneListView.as_view(), name='zone_list'),
+    url(r'^zones/(?P<pk>\d+)/$', ZoneDetailView.as_view(), name='zone_detail'),
+
+    # Records
+    url(r'^records/$', RecordListView.as_view(), name='record_list'),
+    url(r'^records/(?P<pk>\d+)/$', RecordDetailView.as_view(), name='record_detail'),
+
+    # BIND Exports
+    url(r'^bind/forward/$', bind_forward, name='bind_forward'),
+    url(r'^bind/reverse/$', bind_reverse, name='bind_reverse'),
+
+]

netbox/dns/api/views.py

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+from rest_framework import generics
+from django.http import HttpResponse
+
+from rest_framework.decorators import api_view
+from rest_framework.response import Response
+
+from ipam.models import IPAddress
+from dns.models import Zone, Record, export_bind_forward, export_bind_reverse
+from dns import filters
+
+from . import serializers
+
+#
+# Zones
+#
+
+
+class ZoneListView(generics.ListAPIView):
+    """
+    List all zones
+    """
+    queryset = Zone.objects.all()
+    serializer_class = serializers.ZoneSerializer
+    filter_class = filters.ZoneFilter
+
+
+class ZoneDetailView(generics.RetrieveAPIView):
+    """
+    Retrieve a single zone
+    """
+    queryset = Zone.objects.all()
+    serializer_class = serializers.ZoneSerializer
+
+
+#
+# Records
+#
+
+
+class RecordListView(generics.ListAPIView):
+    """
+    List all records
+    """
+    queryset = Record.objects.all()
+    serializer_class = serializers.RecordSerializer
+
+
+class RecordDetailView(generics.RetrieveAPIView):
+    """
+    Retrieve a single record
+    """
+    queryset = Record.objects.all()
+    serializer_class = serializers.RecordSerializer
+
+
+#
+# BIND Exports
+#
+
+
+@api_view(['GET'])
+def bind_forward(request):
+    """
+    Full export of forward zones in BIND format
+    """
+    zones_list = export_bind_forward()
+    return Response(zones_list)
+
+
+@api_view(['GET'])
+def bind_reverse(request):
+    """
+    Full export of reverse zones in BIND format
+    """
+    zones_list = export_bind_reverse()
+    return Response(zones_list)

netbox/dns/apps.py

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+from django.apps import AppConfig
+
+
+class DNSConfig(AppConfig):
+    name = 'dns'
+    verbose_name = 'DNS'

netbox/dns/filters.py

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+import django_filters
+from django.db.models import Q
+
+from ipam.models import IPAddress
+from .models import (
+    Zone,
+    Record,
+)
+from .forms import record_type_choices
+
+
+class ZoneFilter(django_filters.FilterSet):
+    name = django_filters.CharFilter(
+        name='name',
+        lookup_type='icontains',
+        label='Name',
+    )
+
+    class Meta:
+        model = Zone
+        fields = ['name']
+
+
+class RecordFilter(django_filters.FilterSet):
+    zone__name = django_filters.ModelMultipleChoiceFilter(
+        name='zone__name',
+        to_field_name='name',
+        lookup_type='icontains',
+        queryset=Zone.objects.all(),
+        label='Zone (Name)',
+    )
+    record_type = django_filters.MultipleChoiceFilter(
+        name='record_type',
+        label='Type',
+        choices=record_type_choices
+    )
+    name = django_filters.CharFilter(
+        name='name',
+        lookup_type='icontains',
+        label='Name',
+    )
+    name_or_value_or_ip = django_filters.MethodFilter(
+        name='name_or_value_or_ip',
+    )
+
+    class Meta:
+        model = Record
+        field = ['name', 'record_type', 'value']
+
+    def filter_name_or_value_or_ip(self, queryset, value):
+        if not value:
+            return queryset
+        return queryset.filter(Q(name__icontains=value) | Q(value__icontains=value) | Q(address__address__icontains=value))

netbox/dns/fixtures/dns.json

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+[
+{
+	"model": "dns.zone",
+	"pk": 1,
+	"fields": {
+		"name": "foo.net",
+		"ttl": 10800,
+		"soa_name": "@",
+		"soa_contact": "ns@foo.net. noc@foo.net.",
+		"soa_serial": "2016070401",
+		"soa_refresh": 3600,
+		"soa_retry": 3600,
+		"soa_expire": 604800,
+		"soa_minimum": 1800
+	}
+},
+{
+	"model": "dns.record",
+	"pk": 1,
+	"fields": {
+		"name": "@",
+		"record_type": "NS",
+		"zone": 1,
+		"value": "ns.foo.net."
+	}
+},
+{
+	"model": "dns.record",
+	"pk": 2,
+	"fields": {
+		"name": "www",
+		"record_type": "A",
+		"zone": 1,
+		"address": 1
+	}
+}
+]

netbox/dns/formfields.py

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+from netaddr import IPNetwork, AddrFormatError
+import netaddr
+
+from django import forms
+from django.core.exceptions import ValidationError
+
+from ipam.models import IPAddress, Prefix
+
+
+#
+# Form fields
+#
+
+class AddressFormField(forms.Field):
+    default_error_messages = {
+        'invalid': "Enter a valid IPv4 or IPv6 address (with CIDR mask).",
+    }
+
+    def to_python(self, value):
+        if not value:
+            return None
+
+        # Ensure that a subnet mask has been specified. This prevents IPs from defaulting to a /32 or /128.
+        if len(value.split('/')) != 2:
+            raise ValidationError('CIDR mask (e.g. /24) is required.')
+
+        try:
+            net = IPNetwork(value)
+        except AddrFormatError:
+            raise ValidationError("Please specify a valid IPv4 or IPv6 address.")
+
+        ip = IPAddress.objects.filter(address=value)
+        if not ip:
+            net = IPNetwork(value)
+            obj = IPAddress(address=net)
+            obj.save()
+            return obj
+        else:
+            return ip[0]